A number of items were found after garda divers recovered a bag from the Royal Canal, near Carton House, in Maynooth, north Kildare.

Several body parts were also found in the Grand Canal at the village of Sallins when a bag was retrieved on Sunday. Further bags were located in the same area yesterday.

The equipment, which is currently undergoing forensic examination, does not include a saw or a blade but is a component part of a device, which may have been used by the gang who murdered the 33-year-old west Dublin man last Friday week.

Investigating officers have described the Carton and Sallins finds as significant and said they would provide a significant boost to their inquiries.

Senior gardaí have confirmed that an extensive line in their investigation into the murder of Mr O'Brien is gangland activity.

Chief Superintendent Barry McPolin, of the Kildare Division, said he was satisfied with progress of the investigation.

"We have a very large number of detectives from Kildare division, supported by both national and regional units, working hand in hand and it is our speed and determination to bring the perpetrators of this brutal murder to justice and before the courts," he said.

"We will treat every iota of information that we receive with the strictest of confidence."

He added that previous murders of a similar nature were also being reviewed by the investigation team.

"Quite obviously, as part of the several lines of inquiry, we will be looking at other murders to see are there links and any similarities," he said.

Superintendent Gerry Wall of Leixlip Garda Station said the investigation was wide-ranging.

"It has extensive lines of inquiry and information. As with any murder investigation, we follow every line of inquiry with a slow methodical process.

"That (gangland) could be an aspect of it and we will certainly look at that during our inquiries," Supt Wall said.

The senior garda said the O'Brien family were understandably "very stressed during a traumatic time".

"They are enduring a very seriously stressful time in their lives that nobody would wish on anyone to suffer or endure. They've lost a loved one, a son, a partner, a father, a brother, a cousin. It is indeed a very traumatic time for them," he said.

He revealed that gardaí have so far followed over 300 lines of inquiry during the murder probe and continued to appeal for anyone with information to come forward. One theory being looked at is that the father of one became involved with criminals with whom he grew up in west Dublin.

A source explained that Mr O'Brien was persuaded by an organised crime outfit to hand over cash to fund a drug-dealing network with the promise of a prosperous return on his investment.

"It appears that this gang persuaded him to part with big cash sums on the promise of a return on his investment.

"This may have worked out once or twice before but something went wrong along the way this time," a source said.

"Kenneth was not a gangster. He wasn't into drugs or violence, but he was taken advantage of by people who grew up around him and knew he was making money in Australia," they added.

"He got into something he thought he could handle.

"He thought it was the quickest way to turn a profit on his money and provide for his family's future but something went wrong somewhere."